Strokes are currently the third leading cause of death in the United States, causing approximately 177,000 deaths per year, and strokes are currently the number one cause of long-term disability in the United States, affecting nearly 5 million people. Strokes are caused by an abrupt interruption of the blood supply to the brain or spinal cord, thereby depriving the tissue of oxygen and resulting in tissue damage.
Strokes typically occur in one of two forms: (i) hemorrhagic stokes, which occur with the rupture of a blood vessel; and (ii) ischemic strokes, which occur with the obstruction of a blood vessel.
Rapid diagnosis is a key component of stroke treatment. This is because the treatment for an ischemic stroke may be contra-indicated for the treatment for a hemorrhagic stroke and, furthermore, the effectiveness of a particular treatment may be time-sensitive. More particularly, the current preferred treatment for an acute ischemic stroke, i.e., the administration of tPA to eliminate blood clots, is contra-indicated for a hemorrhagic stroke. Furthermore, the clinical data suggests that the medication used to treat ischemic strokes (i.e., tPA.) is most effective if it is administered within 3 hours of the onset of the stroke. However, current diagnosis times, i.e., the time needed to identify that the patient is suffering from a stroke and to identify the hemorrhagic or ischemic nature of the stroke, frequently exceeds this 3 hour window. As a result, only a fraction of current ischemic stroke victims are timely treated with tPA.
Imaging is generally necessary to properly diagnose (and hence properly treat) a stroke. More particularly, imaging is generally necessary to: (i) distinguish strokes from other medical conditions; (ii) distinguish between the different types of strokes (i.e., hemorrhagic or ischemic); and (iii) determine appropriate treatments (e.g., the administration of tPA in the case of an ischemic stroke).
Computerized Tomography (CT) has emerged as the key imaging modality in the diagnosis of strokes. CT imaging systems generally operate by directing X-rays into the body from a variety of positions, detecting the X-rays passing through the body, and then processing the detected X-rays so as to build a computer model of the patient's anatomy. This computer model can then be visualized so as to provide images of the patient's anatomy. It has been found that such CT scanning, including non-enhanced CT scanning, CT angiography scanning and CT perfusion scanning, is able to provide substantially all of the information needed to effectively diagnose (and hence properly treat) a stroke.
Unfortunately, in practice, the CT imaging system is typically located in the hospital's radiology department and the patient is typically received in the hospital's emergency room, and the “round-trip” time between the emergency room and the radiology department can frequently involve substantial delays, even in the best of hospitals. As a result, the time spent in transporting the patient from the emergency room to the radiology department and then back again can consume critical time which can compromise proper treatment of the patient (e.g., it can prevent ischemic stroke victims from being timely treated with tPA).
Thus, there is an urgent need for a new and improved CT imaging system which is particularly well suited for use in stroke applications. More particularly, there is an urgent need for a small, mobile CT imaging system which can be pre-positioned in the emergency room and moved to the patient so that the patient can be scanned at their current location, thus effectively eliminating “round-trip” delays and dramatically reducing the time needed to properly diagnose the patient. It is also important that the CT imaging system be relatively inexpensive, so as to facilitate its rapid proliferation and widespread use, e.g., pre-positioning in substantially all hospital emergency rooms and wide availability in outlying, low-volume settings (e.g., rural hospitals, ships, etc.).
In this respect it should also be appreciated that current CT imaging systems are generally quite complex, in both a mechanical sense and in an electrical sense. This is due to the general nature of CT imaging systems.
More particularly, current CT imaging systems generally comprise a frame which supports a rotating drum assembly having a center opening, an X-ray tube assembly adapted to emit X-rays, and an X-ray detector assembly adapted to detect X-rays. The X-ray tube assembly and the X-ray detector assembly are mounted to the rotating drum assembly about the center opening, in diametrically-opposing relation, such that the X-ray beam (generated by the X-ray tube assembly and detected by the X-ray detector assembly) is passed through the interior of the drum assembly (i.e., across the center opening), and hence is passed through patient anatomy disposed within the interior of the rotating drum assembly (i.e., patient anatomy disposed within the center opening). Furthermore, since the X-ray tube assembly and the X-ray detector assembly are mounted on the rotating drum assembly so that they are rotated concentrically about the axis of the rotating drum assembly, the X-ray beam will be passed through the patient's anatomy along a full range of radial positions. As a result, by moving the patient longitudinally through the center opening while passing the X-ray beam through the anatomy along a range of radial positions, the CT imaging system can create the desired computer model of the scanned anatomy. Thus it will be appreciated that CT imaging systems must provide the mechanical systems needed for mounting the rotating drum assembly to the frame in a manner that frictionlessly supports the substantial weight of the rotating drum assembly and its passenger components (e.g., the X-ray tube assembly and the X-ray detector assembly). Due to their nature, the frame, the rotating drum assembly and the mechanical mounts tend to be relatively complex and costly to produce.
Thus, there is a need for a new and improved approach for forming the frame, the rotating drum assembly and the mechanical mounts, and for mounting the rotating drum assembly and its passenger components (e.g., the X-ray tube assembly and the X-ray detector assembly) to the frame, so as to facilitate the provision of a mobile CT imaging system of reduced complexity and reduced cost.